1. Field of the Invention
The invention relates to an information processing apparatus, information processing method and information processing program and, more particularly, to an information processing apparatus, information processing method and information processing program that are able to convert an interlaced video signal into a progressive video signal with less degradation.
2. Description of the Related Art
As shown in FIG. 1, for example, in a front end that includes a decoder, when it is desirable to decode an encoded 60 Hz video signal and then output the decoded 60 Hz video signal from the front end as a 59.94 Hz video signal, it may be necessary to convert a frame rate in the front end. One of frame rate conversion methods includes a method in which a frame or field in a specific place of the decoded picture is skipped. For example, when a 60 Hz video signal is converted into a 59.94 Hz video signal, there is a method in which a 60 Hz decoded picture is skipped one frame for about every 1001 frames and thus converted into a frame rate of 59.94 Hz for output (60*1000/1001≈59.94).
In FIG. 1, a 3:2 pulldown process is performed on a 24p signal to obtain a 3:2 pulldown signal (60i signal). When the 3:2 pulldown signal is converted into a 59.94i signal, two frames (fields) shown by video signals D indicated by “Skip” in the drawing are skipped to achieve frame rate conversion.
On the other hand, as shown in FIG. 2, for example, in a front end that includes a decoder, when it is desired to decode an encoded 59.94 Hz video signal and then output the decoded 59.94 Hz video signal from the front end as a 60 Hz video signal, it may be necessary to convert a frame rate in the front end. One of frame rate conversion methods include a method in which a frame or field in a specific place of the decoded picture is repeated. For example, when a 59.94 Hz video signal is converted into a 60 Hz video signal, there is a method in which a 59.94 Hz decoded picture is repeated one frame for about every 1000 frames and thus converted into a frame rate of 60 Hz for output (59.94*1001/1000≈60).
In FIG. 2, a 3:2 pulldown process is performed on a 23.976p signal to obtain a 3:2 pulldown signal (59.94i signal). When the 3:2 pulldown signal is converted into a 60i signal, frames shown by video signals C and D indicated by “Repeat” in the drawing are repeated to achieve frame rate conversion.
Incidentally, as shown in FIG. 3, when the 3:2 pulldown signal (59.94i signal) obtained by performing the pulldown process on the 23.976p signal is converted into a progressive signal, because skipping or repeating due to frame rate conversion, or the like is not performed, I/P (Interlace/Progressive) conversion provides a 59.94p signal, which is a complete progressive signal.
An existing technique related to the progressive conversion, for example, includes a technique described in Japanese Unexamined Patent Application Publication No. 11-88845.